Generator drive systems of the above-mentioned type typically comprise a traction transmission drive. Presently, primarily flat belts and/or v-ribbed belts are used as traction transmissions, for example so-called poly-v-belts. These belts are pre-stressed via tensioning pulleys. Particularly when starting the internal combustion engine, during the first rotations of the crankshaft, stress can occur within the traction mechanism far exceeding the stress occurring during the regular operation. Particularly in vehicles equipped with automatic motor start-up and shut-down devices, the motor starting processes considerably affect the life of the components of said traction mechanism and the aggregates driven.